Classic WoW raids in order

Vanilla World of Warcraft had seven raids, and they did not arrive together. Molten Core and Onyxia's Lair were in the game from launch in November 2004. The rest opened one patch at a time over the next twenty months, ending with Naxxramas in June 2006. Here is the full order, with the patch and the date each one opened.

Every Vanilla raid, in the order it opened

Molten Core — 40 players — in the game from launch, November 2004 Onyxia's Lair — 40 players — in the game from launch, November 2004 Blackwing Lair — 40 players — patch 1.6, 12 July 2005 Zul'Gurub — 20 players — patch 1.7, 13 September 2005 Ruins of Ahn'Qiraj — 20 players — patch 1.9, 3 January 2006 Temple of Ahn'Qiraj — 40 players — patch 1.9, 3 January 2006 Naxxramas — 40 players — patch 1.11, 20 June 2006 Dates are the North American patch dates from Blizzard's own patch history; Europe usually followed within a day. Zul'Gurub and the Ruins of Ahn'Qiraj are the two 20-player raids — everything else is built for 40.

What else opened along the way

The raids were not the only level-60 content to arrive in that stretch. Dire Maul came with patch 1.3 on 7 March 2005, as a five-player dungeon rather than a raid. The world boss Azuregos arrived in the same patch, and the four Dragons of Nightmare with patch 1.8 on 10 October 2005. Battlegrounds opened earlier than most people remember: Alterac Valley and Warsong Gulch in patch 1.5 on 7 June 2005, Arathi Basin alongside Zul'Gurub in 1.7. The last Vanilla content patch was 1.9; what came after it tuned classes and systems rather than adding raids.

Walking the same road on a fresh realm

A server that opens everything on day one skips the part that made this order matter: a whole realm working through one raid before the next one existed. Stonetavern keeps that shape on both of its worlds, from opposite directions. Elwynn runs the finished ruleset from day one and staggers only the raid and dungeon doors, from Molten Core to Naxxramas across seven chapters. The Barrens moves the whole realm forward through the historical patches instead, and keeps going past Vanilla. Neither is a countdown on a marketing page — the doors are opened by hand, and what opened when is written down.

Questions

How many raids were in Vanilla WoW?
Seven: Molten Core, Onyxia's Lair, Blackwing Lair, Zul'Gurub, the Ruins of Ahn'Qiraj, the Temple of Ahn'Qiraj and Naxxramas. Five are 40-player raids; Zul'Gurub and the Ruins of Ahn'Qiraj take 20.
What was the first raid in WoW?
Molten Core and Onyxia's Lair, both in the game from the November 2004 launch. Neither is listed as introduced in any later 1.x patch note, which is how they can be dated to release rather than to a patch.
What was the last raid in Vanilla WoW?
Naxxramas, added in patch 1.11 on 20 June 2006. Nothing was added after it — the remaining Vanilla patches changed classes and systems, and the next raid content came with The Burning Crusade in January 2007.
What was the final Vanilla patch?
1.12.0, on 22 August 2006. It brought cross-realm battlegrounds and a rogue talent revamp. Because it is the last and most complete state of the original game, 1.12.1 is the version most preservation servers run.
Do private servers open the raids in this order?
It depends entirely on the server, and it is worth checking before you invest a character. Many open everything at once. Stonetavern does not: Elwynn opens the doors one chapter at a time, and the Barrens advances the whole realm through the historical patches.

See where a realm actually is on that road

The chapter roadmap and the progression page say which doors are open today, which one is next, and who decided it. No countdown timers, no fake urgency.